The concept of utilizing squish jets in combustion chambers to increase turbulence of the air fuel mixture within the combustion chamber is known. One of the most recent designs wherein squish jets (for air or air fuel mixtures) are directed into a bowl in a manner to increase the turbulence of the air fuel mixture, particularly within the bowl, by interference between jets is disclosed in U.S. Pat. No. 4,572,123 issued Feb. 25, 1986, to Robert L. Evans. In this patent passages are formed through the piston (or cylinder head) from a compression face to discharge into a bowl at locations above the base of the bowl, i.e. between the rim and base of the bowl, the rim being substantially in the plane of the compression face. The air fuel mixture is forced through these passages by the piston movement within the cylinder particularly as the piston approaches the top dead centre position and is driven from the passages to issue as jets into the bowl. The jets are aimed to interact to increase the turbulence of the air fuel mixture in the bowl.
In the arrangement shown in the patent, the passages are tubular and thus are difficult to construct.
Many systems have been proposed where open channels have been formed in the compression face of the piston (or cylinder) leading into a suitably positioned bowl or like structure to direct the mixture of fuel and combustion gas into the bowl as jets of the air fuel mixture to enhance combustion. See for examples see the following patents: Japanese 58-107812 (A) June 1983, and 56-129716 (A) October 1981; German 2919371 November 1980; East German 146322; U.S. Pat. Nos. 1,745,884 issued Feb. 4 1930, 1,754,735 issued Apr. 15, 1930, 2,151,218 issued Mar. 21, 1939, or 4,166,436 issued Sept. 4, 1979.